What exactly are you trying to test?
But honestly, in much the same way that you replied to nom, I am replying to you: play with LS and come back with some concrete observances rather than using hypotheticals and then we can talk.
I'm trying to test LS only. I don't have a decent LS bow/xbow.
What I meant is, you need to play a DH with LS to properly judge how useful it is. Can you judge how good a car is by driving it on a 0-60 test? Sure you can test acceleration that way, but without evaluating the acceleration in relationship to the handling and overall feel of the car you don't really know how to judge that acceleration.
In a similar vein, if LS is LS is LS, then you should just leave the coefficient at the same value as it is for barbarians.
what I mean is some of the stuff you are saying like
"if you have LS you can play without gloom"
"if you have LS then just find some white mobs to kill along with your RD elites"
you really need to play a DH with LS to see how viable those statements are.
2nd edit: assuming you are vaulting, the dynamics of DH and wizard (at least from what I've played of my level 60 wizard, which granted isn't a ton) imo are pretty different.